Folding helmet



FIG. 1 is a front perspective view of a folding helmet, in an unfolded position, showing the new design;

FIG. 2 is a front view of thereof, in the unfolded position;

FIG. 3 is a back view of thereof, in the unfolded position;

FIG. 4 is a side view of thereof, with the opposite side view being a mirror image thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a front perspective view thereof, in a folded position.

In all figures, any showing of the environment and/or drawing disclosure and/or vents by broken lines is for illustrative purposes only and forms no part of the claimed design. 

CLAIM The ornamental design for a folding helmet, as shown and described. 